Apparatus for controlling and optimizing the production of chemical substances are well known in the prior art. Factors affecting the design of chemical production equipment and of controlling the equipment include the chemical properties of the desired product and the reactants used, the temperature and pressure required, and the required product volume or production rate. Chemical processing equipment can be specifically designed for a particular reaction, or can be designed to be more generally applicable to a variety of chemical reactions.
For example, the chemical processing equipment employed in large scale production facilities is often optimized for high volume production of a single desired product. In contrast, research laboratories typically use chemical processing equipment designed to produce relatively small volumes of many different products.
Chemical reactors that can be used for more than a single chemical reaction are most suited in processes that require several different sequential reactions. For example, in research settings, small volumes of a number of different yet closely related chemicals may be required, requiring that a series of related yet different chemical manipulations be executed. For such an application, a single reactor can be used to sequentially produce a plurality of different products, by continually providing the reactor with different mixtures of reagents. When the research is directed toward determining optimum parameters for producing a single product, different small batches of the same product are often sequentially produced, under varying process conditions, so that the optimal reaction parameters can be determined.
One of the highest costs of research is associated with skilled labor. Accordingly, it is preferable to automate chemical processing systems used in a research environment to the extent practical. Indeed, it would be desirable to employ a fully automated chemical processing system that is capable of operating continually with minimal operator supervision to generate the desired products. Such a system should preferably include a reactant supply system capable of providing a variety of different selected reactants upon command, so that a plurality of different products can be sequentially produced without operator supervision. Such a system would likely require a product collector capable of separately storing the different desired products that are produced.
U.S. Pat. No. 5,324,483 (Cody et al.) describes a device that includes a plurality of chemical reactors operating in parallel and having the ability to simultaneously synthesize many different compounds. However, given the available space and funding constraints under which many research facilities operate, it would be preferable to employ an automated system with a single reactor that operates continually, with minimal operator attention over a period of time, to provide different selected desired products.
To produce some types of desired products, reactants must undergo a sequence of reactions. Again, in a research laboratory, it would be preferable to carry out such reactions using a single chemical processing system. For example, in the field of biotechnology, many sequential reactions are often required to produce a desired product. Peptides, which are sequences of amino acids, are extremely useful research chemicals that are produced by successively adding selected different amino acids, in the proper order, to a base amino acid or peptide. U.S. Pat. No. 4,748,002 (Neimark) describes a semi-automated chemical processing system optimized to produce different peptides. The system includes a plurality of different reaction chambers operating independently of each other. A reaction chamber is charged with a base amino acid, and the desired peptide is produced by adding additional amino acids with the base amino acid, one by one. Between reactions, the current intermediate product is stabilized and rinsed before a new reaction is initiated by adding the next amino acid. The desired product is not removed from the system until the last amino acid in the sequence has been added, and the entire process may require up to 10 days. While the system disclosed by Neimark enables sequential reactions to be achieved, by its design, the system is optimized and essentially dedicated to the task of synthesizing peptides, and is not useful for most other chemical processing needs.
Recently, much attention has been directed to the use of micro-scale reactors both for the development and production of chemical products, particularly in research applications. Chemical processing systems that employ microreactors offer several clear advantages over more conventional macro-scale chemical processing systems related to cost and efficiency. Accordingly, it would be desirable to provide a sequential chemical processing system that employs a microreactor. The prior art does not teach or suggest such an automated, sequential microreactor-based chemical processing system. By operating continuously, such a system can readily be employed in accumulating substance libraries that will be useful in many different research applications.